The invention is directed to a device used in the refining of aluminum, i.e., smelting, in which a pneumatically driven hammer is employed for punching through the crust that develops on top of the molten refined aluminum-electrolyte, and there is an alumina dispenser cup or chamber that fills with alumina (typically comminuted into a powder form) and then the cup dispenses the alumina when the hammer is driven downward. A suitable crust punch and alumina dispenser device is described in our prior U.S. Pat. No. 7,892,319, granted Feb. 22, 2011.
In this improvement, a generally cylindrical-shaped dose meter or alumina flow limiter is positioned onto the shaft of the crust breaker within the space of the dispenser cup and just above the valve seat. The alumina dust fills the cup when the crust breaker shaft is raised, and then when the crust breaker descends the valve seat pulls away from the lower rim of the cup and the alumina then pours out onto the molten material in the aluminum smelting pot. The objective of the dose meter is to slow down the flow of the alumina powder so that it is not dumped in all at once, but flows out over a period of several seconds. To that end, the cylinder-shaped dose meter is spaced a short distance above the top surface of the valve seat and there are also a number of cutouts in the lower rim of the dose meter. This ensures that the entire dose will flow out, and the space between the dose meter and the valve seat flows the material out so that the alumina material does not clog behind the dose meter. The dose meter ensures a more regulated rate of flow of the alumina powder.
The flow-regulating or flow-limiting device can take the form of a generally cylindrical sleeve that fits inside the cup or dose holder and may optionally have a small stand-off between the bottom edge and the valve cone, and also may have notches or cutouts in the lower edge, so that when the cup is opened, the aluminum ore flows in a slower stream instead of being dumped in suddenly into the molten electrolyte in the aluminum smelting pot. Favorably, the dose meter is to be used with a combination crust breaking and alumina feeding device, capable of both dosing and crust breaking, or dosing alone or crust breaking alone. Embodiments of the dose meter can be in the form of two identical halves that bolt together on the chisel shaft above the valve seat, with notches cut out of the bottom edge, and possibly with feet or standoffs to keep the lower edge of the dose meter a small distance above the valve seat. Other embodiments may be formed of three, four, or more components that bolt or fasten together about the chisel shaft.
The combination crust breaker and ore feeder or dispenser can be of the type described in our earlier U.S. Pat. No. 7,892,319, which is incorporated herein by reference, or for example in U.S. patents to Kissane, U.S. Pat. No. 5,423,968 or U.S. Pat. No. 5,324,408.